Electronic circuit packages including a plurality of integrated circuit chips are widely used in a variety of well-known applications from computers to computer controls of a wide variety of devices, for example, automobiles and home appliances, among others. Electronic circuit packages for complex systems typically are comprised of a multiplicity of interconnected integrated circuit chips. The integrated circuit chips are usually made from a semiconductor material such as silicon or gallium arsenide. Microscopic circuits are formed in the various layers of the integrated circuit chips using known photolithographic techniques. The integrated circuit chips may be mounted in packages which are then mounted on printed wiring boards. Packages including integrated circuit chips typically have numerous external pins which are mechanically attached by solder or a variety of other known techniques to conductor patterns on the printed wiring board.
Typically, the packages on which these integrated semiconductor chips are mounted include a substrate or other chip mounting device. One example of such a substrate is a leadframe. High performance leadframes typically are multi-layer structures including power, ground, and signal planes. Leadframes also typically include at least an area on which an semiconductor integrated chip is mounted and a plurality of power, ground, and/or signal leads to which power, ground, and/or signal sites of the integrated semiconductor chip are electronically attached. Semiconductor integrated chips may be attached to the leadframe using adhesive or any other techniques for attaching such chips to a leadframe which are commonly known to those skilled in the art, such as soldering. The power, ground and signal sites on the chip may then be electrically connected to selected power, ground and signal plane or individual leads of the leadframe.
Once the integrated circuit chip(s) are attached to the leadframe, the leadframe may be enclosed or encapsulated in a protective enclosure. Such enclosures may include encapsulation in a plastic or a multi-part housing made of plastic, ceramic, or metal. The enclosure may protect the leadframe and the attached chip from physical, electrical, and/or chemical damage. The leadframe and attached chip(s) may then be mounted on, for example, a circuit board or card along with other leadframes or devices. The circuit board or card may then be incorporated into a wide variety of devices such as computers, automobiles, appliances, among others.
Typical known leadframes which include a plurality of layers are complex and expensive to produce. The multiple planes were included in the design of known leadframes as a solution to accommodate the high density of leads in the highly integrated circuits typically used today. The multiple planes having a single function, such as ground, power, and signal, were incorporated in a design of frames as an attempt to electrically isolate the various planes to reduce electrical interference, such as noise, among the planes. The layers must be built up using known techniques. Therefore, the multi-layer leadframe, although functionally effective, is very complex and not cost effective.